An article entitled "Garbage In, Megawatts Out" recently appeared in MIT
Technology Review at the web site:
www.technologyreview.com/Energy/21029/. This article gives a glowing
picture of plasma arc gasification of waste while ignoring the downside.
I have posted the comments below to the TR website and sent them to an
Ottawa newspaper, etc.
Emeritus professor of physics
The article entitled “Garbage In, Megawatts Out” appeared on July 02 in
the MIT /Technology Review/ reporting that the city of Ottawa, Ontario
had approved a gasification facility that would use 400 metric tons/day
(equal to 880 US tons) to produce 21 megawatts of electricity. Before
this is hailed as a breakthrough for turning waste into energy, it
deserves further scrutiny. It must be compared with recycling on the
basis of the energy produced, effects on the environment, and the economy.
* Energy—Using the energy content of the waste consumed, the
efficiency of the Ottawa facility can be calculated to be below
20%. For each ton of material used for fuel, another ton must be
produced from virgin materials to replace it. The US EPA has
supplied data on the energy required to produce a ton of each
constituent of municipal solid waste from both virgin and recycled
materials. The energy saved by recycling is three to five times
that produced using waste as a fuel. Recycling the materials
instead of using them as fuels saves more than the “megawatts out”
even if the thermodynamic limit for energy efficiency could be
* Environment—Producing new products from virgin raw material
requires processes such as mining, use of fossil petroleum for
plastics and fuel, and cutting or growing trees, all of which are
detrimental to the environment, and are not sustainable. Recycling
paper and plastics would mean that fewer trees would be cut from
Canada’s boreal forest and less of Alberta destroyed in extracting
petroleum from oil sands.
* Economy—The EPA-data indicates that recycling the 400 MT/d would
provide 1500 jobs with better pay than the average of all jobs,
and add $25 million (US) to Ottawa’s economy. Recycled materials
are essential to industry. Without recycled paper and cardboard,
e.g., newspapers could not be printed nor products shipped in
Ottawa’s low recycling rate, especially the 17% for commercial waste
that constitutes 70% of the waste, provides the opportunity to recycle
much more of its waste, saving energy and the environment, while
stimulating the economy. Ottawa should follow the lead of San Francisco,
Guelph, Edmonton, or Vancouver with a zero-waste goal.